thyssenkrupp - Active Battery Cooler
We are thankful for the trust of thyssenkrupp Components Technology Hungary Ltd. resulting in great cooperation.
For those who are unaware, thyssenkrupp Components Technology Hungary Ltd. is one of the defining, innovative companies of the automotive industry. They established their office in Hungary in 1999 with a small team of engineers. The success of the completed prototype project at that time played a great part in the expansion to other locations in Hungary. Since then, they have multiple sites including the E/E electronic and software development centre in Budapest where multiple development projects take place, such as future-oriented steer-by.wire systems.
Xtalin Ltd. became a partner of thyssenkrupp in 2019. We have worked with them in their projects using the accumulated knowledge both in theory and in practice related to electric vehicles. Since at Xtalin Ltd. all conditions are met to design and implement high voltage automotive systems, we take part in such works at thyssenkrupp's operation site in Budapest.
After smaller tasks, we have been selected to implement a unique battery cooling solution. The project started with getting to know the requirements and limitations which we used to create an exact specification that could be the starting point of the design process.
Since the battery needs to be cooled under the ambient temperature we could only use active cooling and heat pump systems. This solution includes many professions’ areas of expertise (cooling technology, mechanical engineering, embedded systems, high voltage automotive systems, control systems). We had a complicated task ahead of us. The HVAC systems in heat pumps were a new challenge compared to the water-air heat exchangers we used earlier. We have started the project with confidence under X_ABC codename.
As a first step, we created a mathematical model to support the cooling design with accurate calculations. Based on this, we determined the requirements for the main units.
The selection of major components and suppliers is very important during the design phase. Only high-quality, well-documented components from a reliable source can be used to develop a product that works reliably and we can only guarantee this if such conditions are met.
We have a fully developed general-purpose control electronics, the X_VCU, whose peripherals also serve the needs perfectly in this application, so there was no question that this unit would be the “brain” of the cooler.
Mechanical design was done in collaboration with one of our mechanical engineering partners. During the design, the employees of Xtalin Ltd. determined the development directions and criteria, and our mechanical partner implemented the plans of the frame and the refrigerant gas pipes, considering manufacturability and relevant standards.
Refrigeration systems can only be modified and installed by a qualified specialist, so we had to find an external company for this job. We needed not only service but also professional consulting and the production of individual refrigerant pipes. This is how we met Hüllő Kft., they were very supportive during the project and contributed their advice to the development of the final design.
It was a good feeling to experience that in all areas you can meet small domestic companies where employees do their work with serious expertise and dedication. Thanks to our partners mentioned above for working together!
Due to the long service life and structural stability, the frame of the equipment was made entirely of stainless steel. This not only provides perfect mechanical protection for the components inside, but also gives the product a very good look.
The production of machined aluminum parts was carried out by our partners, and the aluminum pipes belonging to the refrigeration system were made by Hüllő Kft.
The assembly was followed by a (nitrogen) pressure test, which (could have) revealed the slightest misalignment or leakage defect. Thanks to the careful design, excellent production and thorough, professional assembly, the system was tested flawlessly for the first time, so at Hüllő Kft. it was filled with refrigerant gas and the actual testing phase has started.
It was not possible to test the equipment at its final location, so a test environment was also developed for this purpose. For this the testing parameters and measurement methods had to be established.
We created two independent measurement circuits for testing, in which both the control and the data collection are also performed by an X_VCU. Each measuring circuit consists of a large thermally insulated buffer tank, a water pump and several sensors. With these we can measure the heat transfer performance, and the temperature and the flow rate of the liquid at several points.
For efficient testing, a PC software has been developed so we can monitor and control all the parameters of the cooling system and the test environment.
This way a measurement set-up was created where we can validate all the expected operating characteristics in the previously determined ranges of operation (min-max temperature, volumetric flow rate) described in the specification.
In addition to the basic functions, the embedded software of X_ABC is equipped with self-protection functions, therefore the system is protected against possible errors.
The tests were proceeding at a good pace and we didn’t experience any serious problems. We are proud of this, as this was the first cooler of this type we developed. In addition, its performance has exceeded the expectations, generating 4000W of cooling power using just 1300W of electrical power. For many, this may seem strange at first, of course, 5300W of power is delivered to the environment as heat, mainly through a dedicated cooling circuit.
After completing the tests, we have awaited the day of delivery with great excitement, as the most important thing is the customer's feedback on the finished product.
After the installation of the cooler and the static tests, we also checked the proper operation on a test track in the summer heat. During the tests, it was clear that the refrigeration unit has kept the batteries at a much lower temperature than before and met the expectations.
It was great to work on a project, which requires a new knowledge base for Xtalin Ltd. and is full of challenges. Thanks to the finished product, thyssenkrupp Components Technology Hungary Kft. will be able to carry out its work in the field of automotive innovation more efficiently, and it gave us a great motivation during the development. With this project - even if only to a small extent - we were able to contribute to the future of the automotive industry.
Thanks to the successful project and a good relationship, we will continue to work together. Xtalin Ltd. will always be open to projects like X_ABC, which belong to the edge of our expertise and provide opportunities for innovation within the company.
Competencies used in this project:
- Embedded HW design
- Complex system design
- Multilayer PCB
- Embedded SW design
- Complex fail-safe functions
- Real-time OS
- Other SW design
- PC diagnostic (Java)
- Wire harness
- High current, high voltage (<600V) wiring
- Low voltage
- Mechanical design
- Guidance for stress and tolerance calculations
- Designing simple brackets
- Cooling and refrigeration circuit design
- Manual labour
- Dis/assembly of the product
- Installation of the product
- Manufacturing wire harnesses
- Develop/improve measurement equipment
- Automated measurements and data collection
- Test plans
- Production management
- Ordering components
- Coordinating PCB manufacturing service
- Coordinating machining service
- Project management